The present invention relates to lighted footwear and, more particularly, to footwear with light modules that apply power from a power source in such a way as to turn on the lights so the safety of the wearer is improved, the useful life of the power source is extended and an attractive lighting pattern is created.
At various times in the past, lighted footwear has enjoyed some popularity. This lighted footwear all has the same basic components, i.e., at least one light source, a source of power for the light or lights, and a switch of some sort to apply the output of the power source to the light to cause it to come on and provide illumination. The lights can be of a variety of types, e.g., incandescent bulbs, electro-luminescent panels, and light emitting diodes (LEDs). These are popular lights for this purpose because they can be lighted by the power from small batteries, so that the elements lighting the light can be encapsulated in the footwear and need not be connected to any external power source. However, there is no reason that light sources which require a.c. voltage or current, such as fluorescent lights, could not be used in lighted footwear, assuming a suitable power source were provided. Consequently, as used in this application, "light source" is intended to encompass any device capable of generating detectible light, visible or otherwise, e.g., infrared.
In its simplest form, lighted footwear typically has lights in the heel and along the sole of the footwear, which could be athletic shoes, casual shoes, formal shoes or sandals for men, women or children. A battery, e.g, of three (3) volts output, is incorporated in the heel or sole of the shoe and is connected by wires to the lights. A switch is provided in the connecting wires to control the illumination of the lights, which switch may be a simple manual switch as disclosed in U.S. Pat. No. 4,158,922 of Dana, III. Thus, whenever the user wishes the lights to be on, for example, just before he or she goes jogging at night, he or she can turn on the lights by operating the switch. However, with such an arrangement the lights would be on continuously until the switch is turned off.
If the lights are flashed intermittently, there are two advantages. First, the life of the battery is increased in proportion to the time the lights are off during the intermittent flashing. Second, a more attractive eye-catching display is provided. When running at night, the flashing of the lights makes the user more visible, e.g., to motorist, so that the safety of the user is increased. One way to achieve a flashing effect is to utilize a motion-activated switch to apply power to the lights. This could be a mercury switch which is in the form of a tube containing a quantity of mercury and having spaced-apart electrical contacts. The tube is oriented on the footwear so that when the footwear is flat, there is no connection between the contacts. However, as the footwear is tilted, as during the taking of a step, the mercury runs down the tube and closes the contacts. This contact is broken again when the footwear is flat again at the completion of the step. Thus, as the user walks, the lights come on and go off. Mercury switch operated lighted footwear is disclosed in U.S. Pat. No. 4,848,009 of Rodgers and the Dana III '922 patent mentioned above.
In another form of motion-activated switch, the mercury in a mercury switch is replaced for environmental reasons with a metal ball that rolls in the tube. Further, mechanical motion activation can be achieved by the mechanical lever system disclosed in U.S. Pat. No. 2,572,760 of Rikelman. In addition, intermittent operation of the lights can be achieved by a pressure switch. During jogging, whenever the wearer's foot hits the ground the pressure activates a switch in the shoe which closes the circuit and causes the lights to flash. Such a pressure switch is disclosed in European Patent Application No. 0 121 026 of Dana III.
Another way to achieve an intermittent lighting effect is to incorporate an electronic circuit into the flashing footwear. This circuit could be an integrated circuit low frequency oscillator or flasher operated by the switch and providing the power to the lights. Whenever the switch is closed the oscillator provides power to the lights at a slow rate, e.g., from 0.5 to 2.5 Hz. Such a flasher could be like the National Semiconductor LM3909 LED Flasher/Oscillator. Use of this device to provide intermittent lighting is disclosed in the Dana III European patent application. The U.S. Pat. No. 4,158,922 of Dana III also discloses a low frequency oscillator made from individual components which is used in this fashion.
One problem with these prior motion-activated switches, e.g., the mercury, ball, lever and pressure switches, is that they can remain continuously closed, thus allowing the lights to stay on and running the battery down. For example, if shoes with the mercury, ball or lever switches are placed at an attitude corresponding to a step in walking, the switch will close and the lights will light continuously. With the pressure switch, if the wearer is merely standing in one place for too long, the lights will remain on and premature exhaustion of the battery will occur. Similarly, the shoes with the pressure switch can be packed so there is enough pressure on the switch that these lights are on. If shoes with any of these switches are in transit from the factory to the store shelves at an attitude or under sufficient pressure to cause the lights to be on, the flashing effect may no longer work at the time an attempt is made to sell the product to the ultimate user or soon after the sale. This can cause customer complaints and returns of the merchandise.
An electronic solution to the problem of premature battery exhaustion is disclosed in U.S. Pat. No. 4,848,009 of Rodgers. The Rodgers patent proposes that the power to light the lights be provided from the battery through a circuit. This circuit is than controlled by the switch and a further timing circuit so that when the switch closes the circuit provides power to the light and starts the timing circuit. After a predetermined period of time the timing circuit signals the power circuit to cut off the power to the lights. Power cannot be reapplied to the lights until the switch opens and closes again. This results in a single illumination of the lights for a fixed period of time in response to the closure of the switch.
An alternative arrangement for avoiding premature battery exhaustion is provided in U.S. Pat. No. 5,408,764 of Wut. The Wut arrangement uses a battery, lights and a spring switch. The spring switch is in the form of a coil of spring wire which is cantilevered over an electrical contact on a printed circuit board. The other end of the spring is also connected to an electrical contact. Whenever a sufficiently large jolt is given to the switch, a module containing the switch, or a shoe containing the switch, the coil of wire will swing until the end portion of the coil comes into contact with the printed circuit board contact, thus closing the circuit and supplying power to light the lights. Wut teaches placing plastic weight on top of the spring to enhance its downward motion.
Once the end of the spring in the Wut switch comes into contact with the printed circuit board, its momentum is transferred to the rest of the assembly and the spring nature of the coil causes it to recoil from the printed circuit board, thus breaking the contact. A spring switch arrangement of this type provides only intermittent contact, so it cannot apply power to the lights for a long period of time and run down the battery. However, the contact period is very short and subject to bounce or jitter, since the motion of the spring (and that of the weight if attached) is interrupted the instant contact is made. Thus, it would be beneficial to provide a spring switch mechanism for lighted footwear which provides a more reliable and longer duration of contact.
A variation of the spring switch used for lighting LEDs is disclosed in U.S. Pat. No. 5,550,721 to Rapisarda. The Rapisarda '721 patent teaches forming a spring switch by placing a coiled spring around one of the leads of the LED and positioning the spring inside a hollow portion of a conductor mounted on one terminal of the battery. The other LED lead is connected to the opposite battery terminal. When force is applied to the assembly, the spring makes intermittent contact with the mounted conductor, closing the circuit and causing the LED to light. Rapisarda '721 discloses that a blinking lighting effect can be obtained by cantilevering the spring beyond its supporting LED lead and the conductor, in order to allow the spring to oscillate and make repeated contact with the conductor for a period of time after force is applied. The sensitivity of the switch and the duration of the blinking effect can be adjusted by changing the length of the spring extending beyond the contact point. However, this arrangement is only suitable for lighting a single LED since the LED, battery, and switch are physically integrated with each other and no room is provided to add a separate switching circuit. In addition, because one terminal of the switch (the LED lead) is completely encompassed by the other terminal (the spring), there is little tolerance for component variations introduced during manufacturing and assembly.
U.S. Pat. No. 5,644,858 to Bemis discloses another variation of an oscillating spring switch. One terminal of the switch is formed by a coil spring fixed at one end and having a conductive weight, such as a steel ball, affixed to the other end. The second switch terminal is formed of a conductive surface arranged around the weight. When force is exerted on the switch, the spring-weight system oscillates and the weight makes repeated contact with the opposing conductive surface and causes the light to blink. However, as with the Wut switch, the motion of the spring is interrupted at the moment the weight makes contact with the opposing conductor and closes the switch. Thus, the period of contact is very short and subject to bounce or jitter. Furthermore, the flashing display produced by the Bemis module is limited to the brief interval during which the spring continues to oscillate.
In U.S. Pat. No. 5,477,435 to Rapisarda et al., a spring switch is formed by connecting one lead of an LED directly to a battery terminal and cantilevering the other LED over the opposite battery terminal. When the assembly is jarred sufficiently, the cantilevered LED lead makes contact with the battery and causes the LED to briefly light. A weight is placed on top of cantilevered lead to increase the inertia of the lead. As in the Rapisarda '721 patent, this assembly is only suitable for lighting a single LED since the LED and battery are physically integrated with each other to form the switch assembly and no room is provided to add a separate switching circuit.
U.S. Pat. No. 5,419,016 to Barrocas discloses a lighting module which utilizes a spring switch similar to that disclosed in the Rapisarda '721 patent. The switch is formed by a coil spring with a free end, which has a straight wire running through its center. When sufficient force is exerted on the spring, the free end makes intermittent contact with the straight wire, thus closing the switch. However, as in the Rapisarda '721 patent, one terminal of the switch is completely encompassed by the other terminal. Thus, there is little tolerance for component variations introduced during manufacturing and assembly.
It is known to provide enhanced attractiveness to flashing footwear by providing sequential lighting of a plurality of lights, instead of mere intermittent lighting. Thus, for example, if there were three lights on the shoe, each switch closure would cause them to light in sequence, as opposed to simultaneously, and the sequence could be repeated two or more times.
The Rodgers and Wut patent designs provide single illuminations of the lights when the foot hits the ground during walking or jogging. The Rapisarda '721 and Bemis designs allows lighting to occur for a small period of time after the initial illumination. However, the time period is limited to the duration of the spring oscillation and, like in the Rapisarda '435 patent, the design only provides for a simple on-off sequence for a single LED. The Barrocas design provides for multiple lights but, like the design in the Rapisarda '721 patent, requires precision assembly of the switch. Thus, it would also be beneficial to have lighted footwear that could provide coordinated and possibly extended lighting of one or more LEDs in a unique and novel sequence, but still avoid the problem of premature battery exhaustion by utilizing an easy to assemble switching assembly.